Many components for gas turbine engines require a coating to withstand the harsh environment in which the components operate. For example, turbine blades and vanes often contain a thermal barrier coating. The coating is applied in a multistage process. First, the raw metal part is cleaned. Second, a bond coating is administered to the components to bind the outer coating to the base metal alloy. Next, a plasma coat of an outer ceramic coating is applied to the bond coating. However, the process and facilities do not necessarily allow for the immediate succession of steps in the coating process. Often, there are hours or days between the cleaning of the part, the application of the bond coating, and the application of the final outer coating. During this time, the parts must be kept clean, and must not be allowed to oxidize.
The existing process in applying coatings to turbine components is to prevent oxidation on unfinished coated parts by submerging the parts in an unsealed purge tank, and continually flowing argon gas into the tank. However, the tank design with a continuous flow of argon is costly due to the continuous loss of argon gas because the tank is not sealed. Thus, there is a need to reduce the argon gas consumption regarding the use of the purge tank.